A wind turbine generates electrical energy by converting the energy in the wind. The electrical energy can be supplied to the electric power transmission network.
It is known in the art that a wind turbine system is prone to changes in the wind which cause the tower to oscillate back and forth and/or sideways or sometimes in circle-like oscillations. These oscillations reduce the lifetime of the tower and other parts of the wind turbine system. Additionally, the oscillations increase if they match the tower resonant frequency, which reduce the lifetime even more.
It is known in the art that these oscillations can be determined by measuring the acceleration of the wind turbine tower.
US patent application 2009/0230682 A1 discloses an apparatus for determining a resonant frequency of a wind turbine tower. The apparatus includes a processing unit configured to receive an acceleration measurement value, and a memory configured to store a series of acceleration measurement values. The processing unit includes a Fourier transform module configured to calculate a spectral vector based on calculating a convolution-based fast Fourier transform of the series of acceleration measurement values. A resonant frequency calculation module calculates the tower resonant frequency based on the calculated spectral vector.